obtaining and releasing shared and exclusive locks. The algorithms for
manipulating the lock cookie are very similar to that rwlocks. This patch
also adds support for exclusive locks using the same algorithm as mutexes.
A new sx_init_flags() function has been added so that optional flags can be
specified to alter a given locks behavior. The flags include SX_DUPOK,
SX_NOWITNESS, SX_NOPROFILE, and SX_QUITE which are all identical in nature
to the similar flags for mutexes.
Adaptive spinning on select locks may be enabled by enabling the
ADAPTIVE_SX kernel option. Only locks initialized with the SX_ADAPTIVESPIN
flag via sx_init_flags() will adaptively spin.
The common cases for sx_slock(), sx_sunlock(), sx_xlock(), and sx_xunlock()
are now performed inline in non-debug kernels. As a result, <sys/sx.h> now
requires <sys/lock.h> to be included prior to <sys/sx.h>.
The new kernel option SX_NOINLINE can be used to disable the aforementioned
inlining in non-debug kernels.
The size of struct sx has changed, so the kernel ABI is probably greatly
disturbed.
MFC after: 1 month
Submitted by: attilio
Tested by: kris, pjd
Add entries for the six persons listed in the first version of
commit.allow in the old FreeBSD 1 CVS repo.
Correct joergs date, and link him to jkh.
Add my own entry.
Have a look at committers-ports.dot for a start.
Simple command to generate the graph is:
$ dot -T png -o file.png file.dot
Dot can be installed via graphics/graphviz.
Discussed on: -developers
the mutex locked. Also tweak the wording to make it more consistant
between pthread_cond_wait and pthread_cond_tiedwait.
Confirmed with the opengroup's web site that this is a valid return
value. Wording used specifically not that of opengroup's online man
pages.
MFC After: 1 week
imitating an Ethernet device, so vlan(4) and if_bridge(4) can be
attached to it for testing and benchmarking purposes. Its source
can be an introduction to the anatomy of a network interface driver
due to its simplicity as well as to a bunch of comments in it.
argument from a mutex to a lock_object. Add cv_*wait*() wrapper macros
that accept either a mutex, rwlock, or sx lock as the second argument and
convert it to a lock_object and then call _cv_*wait*(). Basically, the
visible difference is that you can now use rwlocks and sx locks with
condition variables using the same API as with mutexes.
This is supposed to be a brief overview of the locking primatives.
It is not yet complete and contains many place-holders for information
I do not know.
The locking is getting so diverse that I've lost track of it all.
We need this page to keep outselves in sync with what the primitives do.
note.. not part of the build yet.
the background fsck indefinitely. This allows the administrator to run
it at a convenient time. To support running it from cron, the
forcestart argument now causes the fsck to start with no delay and all
output to be suppressed.
event. Locking primitives that support this (mtx, rw, and sx) now each
include their own foo_sleep() routine.
- Rename msleep() to _sleep() and change it's 'struct mtx' object to a
'struct lock_object' pointer. _sleep() uses the recently added
lc_unlock() and lc_lock() function pointers for the lock class of the
specified lock to release the lock while the thread is suspended.
- Add wrappers around _sleep() for mutexes (mtx_sleep()), rw locks
(rw_sleep()), and sx locks (sx_sleep()). msleep() still exists and
is now identical to mtx_sleep(), but it is deprecated.
- Rename SLEEPQ_MSLEEP to SLEEPQ_SLEEP.
- Rewrite much of sleep.9 to not be msleep(9) centric.
- Flesh out the 'RETURN VALUES' section in sleep.9 and add an 'ERRORS'
section.
- Add __nonnull(1) to _sleep() and msleep_spin() so that the compiler will
warn if you try to pass a NULL wait channel. The functions already have
a KASSERT to that effect.
interrupt sleeps. Rather, unmasked signals interrupt restarts and can
either interrupt the system call by having it return EINTR in userland or
force the system call to be restarted.
- Don't claim that the mutex is atomically reacquired when a cv_wait
routine returns. There's nothing atomic or magical about the lock
reacquire. The only magic is that we atomically drop the lock by
placing the thread on the sleep queue before dropping the lock.
- Markup sx_unlock() as a function rather than saying it is a macro.
The macro part is an implementation detail, and all the other sx_*lock()
functions are actually macros, too.
- Use the same style as rwlock(9) and mutex(9) to markup sx_assert() and
SX_SYSINIT() with respect to headers and kernel options.
- Add a missing MLINK.
for /tmp and /var. This makes the memory discs swap-backed instead
of malloc-backed. A swap-backed memory disc should not be worse
than a malloc-backed one in any scenario because it will start
touching swap only when needed. OTOH, a malloc-backed disc can
starve limited kernel resources and evenually crash the system.
Reflect the change in the rc.conf(5) manpage. Also stop telling
lies there about softupdates: it does not waste disc space, it
just can delay its freeing.
Suggested by: many
PR: kern/87255
MFC after: 1 week
<sys/extattr.h> to <ufs/ufs/extattr.h>. Move description
of extended attributes in UFS from man9/extattr.9 to
man5/fs.5.
Note that restore will not compile until <sys/extattr.h>
and <ufs/ufs/extattr.h> have been updated.
Suggested by: Robert Watson
While here, remove Xrefs to all other wlan drivers except the Intel ones,
these often get confused. Also remove pointers to the old ipw and iwi webpages,
they don't include any useful information that's not in the manpages yet.
Reviewed by: flz, ru
uuencoded format along with their respective LICENSE files.
- Add new share/doc/legal directory to BSD.usr.dist mtree file. This is the
place we install LICENSE files for restricted firmwares.
- Teach firmware(9) and kmod.mk about licensed firmwares. Restricted firmwares
won't load properly unless legal.<name>.license_ack is set to 1, either
via kenv(1) or /boot/loader.conf.
Reviewed by: mlaier, sam
Permitted by: Intel (via Andrew Wilson)
MFC after: 1 month
o uniform the driver_intr_t parameter name to 'ithread'
o delete any reference to INTR_FAST
o document a bit the difference between the filter and ithread
argument
Reviewed by: mdoc-police (ru)
- the issues with wakeup_one are due to address space clashes between
unrelated groups of threads.
- sleep() was removed in FreeBSD 2.2.
- date the page today, not 4 days ago.
- replace grammatically correct "woken" with "woken up" for
consistency with the function name.
- BIOCGDIRECTION and BIOCSDIRECTION get or set the setting determining
whether incoming, outgoing, or all packets on the interface should be
returned by BPF. Set to BPF_D_IN to see only incoming packets on the
interface. Set to BPF_D_INOUT to see packets originating locally and
remotely on the interface. Set to BPF_D_OUT to see only outgoing
packets on the interface. This setting is initialized to BPF_D_INOUT
by default. BIOCGSEESENT and BIOCSSEESENT are obsoleted by these but
kept for backward compatibility.
- BIOCFEEDBACK sets packet feedback mode. This allows injected packets
to be fed back as input to the interface when output via the interface is
successful. When BPF_D_INOUT direction is set, injected outgoing packet
is not returned by BPF to avoid duplication. This flag is initialized to
zero by default.
Note that libpcap has been modified to support BPF_D_OUT direction for
pcap_setdirection(3) and PCAP_D_OUT direction is functional now.
Reviewed by: rwatson
attribute. Also define some macros to manipulate one of these
structures. Explain their use in the extattr.9 manual page.
The next step will be to make a sweep through the kernel replacing
the old pointer manipulation code. To get an idea of how they would
be used, the ffs_findextattr() function in ufs/ffs/ffs_vnops.c is
currently written as follows:
/*
* Vnode operating to retrieve a named extended attribute.
*
* Locate a particular EA (nspace:name) in the area (ptr:length), and return
* the length of the EA, and possibly the pointer to the entry and to the data.
*/
static int
ffs_findextattr(u_char *ptr, u_int length, int nspace, const char *name,
u_char **eap, u_char **eac)
{
u_char *p, *pe, *pn, *p0;
int eapad1, eapad2, ealength, ealen, nlen;
uint32_t ul;
pe = ptr + length;
nlen = strlen(name);
for (p = ptr; p < pe; p = pn) {
p0 = p;
bcopy(p, &ul, sizeof(ul));
pn = p + ul;
/* make sure this entry is complete */
if (pn > pe)
break;
p += sizeof(uint32_t);
if (*p != nspace)
continue;
p++;
eapad2 = *p++;
if (*p != nlen)
continue;
p++;
if (bcmp(p, name, nlen))
continue;
ealength = sizeof(uint32_t) + 3 + nlen;
eapad1 = 8 - (ealength % 8);
if (eapad1 == 8)
eapad1 = 0;
ealength += eapad1;
ealen = ul - ealength - eapad2;
p += nlen + eapad1;
if (eap != NULL)
*eap = p0;
if (eac != NULL)
*eac = p;
return (ealen);
}
return(-1);
}
After applying the structure and macros, it would look like this:
/*
* Vnode operating to retrieve a named extended attribute.
*
* Locate a particular EA (nspace:name) in the area (ptr:length), and return
* the length of the EA, and possibly the pointer to the entry and to the data.
*/
static int
ffs_findextattr(u_char *ptr, u_int length, int nspace, const char *name,
u_char **eapp, u_char **eac)
{
struct extattr *eap, *eaend;
eaend = (struct extattr *)(ptr + length);
for (eap = (struct extattr *)ptr; eap < eaend; eap = EXTATTR_NEXT(eap)){
/* make sure this entry is complete */
if (EXTATTR_NEXT(eap) > eaend)
break;
if (eap->ea_namespace != nspace ||
eap->ea_namelength != length ||
bcmp(eap->ea_name, name, length))
continue;
if (eapp != NULL)
*eapp = eap;
if (eac != NULL)
*eac = EXTATTR_CONTENT(eap);
return (EXTATTR_CONTENT_SIZE(eap));
}
return(-1);
}
Not only is it considerably shorter, but it hopefully more readable :-)
want an equivalent of DELAY(9) that sleeps instead of spins. It accepts
a wmesg and a timeout and is not interrupted by signals. It uses a private
wait channel that should never be woken up by wakeup(9) or wakeup_one(9).
Glanced at by: phk
transition to mbuma (FreeBSD 5.3) and the fact that mbufs are now limited
almost entirely to packet storage, with straight UMA zones being used for
most other network data types.
Apart from minor cleanup of the text, it should document
in reasonable detail what the status of the code is.
RELENG_6 has some minor differences there in the way automatic
loading/unloading is handled, but hopefully this should be
fixed by MFC time.
The examples come from Max Laier and Sam Leffler.
MFC after: 1 week
